Experimental Study on the Influence of Ultraviolet Laser Parameters on the Micro Machining Quality of Silicon Carbide Ceramic

Abstract

Silicon carbide(SiC) ceramics have great application value in microelectronics and semiconductors due to their small dielectric constant, high thermal conductivity, and small thermal expansion coefficient. However, due to its high hardness and brittleness, defects such as stress concentration, microcracks, and an excessively large heat-affected zone are prone to occur in traditional machining methods. In this paper, the ultra-thin SiC surface was micro-grooved by ultraviolet(UV) laser. The effects and rules of various machining parameters (scanning speed, repetition frequency, pulse width, defocus amount) in UV laser micro-grooves machining on the surface quality, machining depth, and cross-sectional morphology of SiC were studied. The experimental results showed that the surface roughness of SiC micro-grooves decrease with the increase of scanning speed; The relatively small surface roughness (R a 0.72 μm) could be obtained at a scanning speed of 500 mm s−1 and a repetition frequency of 40 kHz; Under low pulse width of 5 ns, high repetition frequency of 50 kHz, and high scanning speed of 500 mm s−1, micro-grooves with a relative error of 2.3% in removal depth could be obtained; The taper of the micro-groove section first decreases and then increases with the defocus from negative to positive, and reached the minimum value of 5° when the defocus positive 0.6 mm.